Juan Manuel Sepúlveda

The Added Value of Apparent Diffusion Coefficient to Cerebral Blood Volume in the Preoperative Grading of Diffuse Gliomas

Is it worth doing both DWI and perfusion imaging in gliomas? These authors sought to study if ADC and rCBV improved diagnostic accuracy in the preoperative grading of gliomas by assessing 162 patients who later underwent surgery. rCBV was significantly different between grade II and IV and between grade III and IV gliomas, but not between grades II and III. ADC values were significantly different for all 3 grades. Conclusion: ADC measurements were better than rCBV values for distinguishing the grades of gliomas, and the combination of minimum ADC and maximum rCBV improved the diagnostic accuracy of glioma grading. BACKGROUND AND PURPOSE: In cerebral gliomas, rCBV correlates with tumor grade and histologic findings of vascular proliferation. Moreover, ADC assesses water diffusivity and is inversely correlated with tumor grade. In the present work, we have studied whether combined rCBV and ADC values improve the diagnostic accuracy of MR imaging in the preoperative grading of gliomas. MATERIALS AND METHODS: One hundred sixty-two patients with histopathologically confirmed diffuse gliomas underwent DWI and DSC. Mean rCBV and ADC values were compared among the tumor groups with the Student t test or ANOVA. ROC analysis was used to determine rCBV and ADC threshold values for glioma grading. RESULTS: rCBV had significantly different values between grade II and IV gliomas and between grade III and IV tumors, but there were no significant differences between grade II and III gliomas (P > .05). Grade II and III tumors also did not differ when astrocytomas, oligodendrogliomas, and oligoastrocytomas were considered separately. ADC values were significantly different for all 3 grades. The ADC threshold value of 1.185 × 10−3 mm2/s and the rCBV cutoff value of 1.74 could be used with high sensitivity in the characterization of high-grade gliomas. The area under the ROC curve for the maximum rCBV and minimum ADC was 0.72 and 0.75, respectively. The combination of rCBV and ADC values increased the area under the ROC curve to 0.83. CONCLUSIONS: ADC measurements are better than rCBV values for distinguishing the grades of gliomas. The combination of minimum ADC and maximum rCBV improves the diagnostic accuracy of glioma grading.

Inhibition of DYRK1A destabilizes EGFR and reduces EGFR-dependent glioblastoma growth.

Glioblastomas (GBMs) are very aggressive tumors that are resistant to conventional chemo- and radiotherapy. New molecular therapeutic strategies are required to effectively eliminate the subpopulation of GBM tumor-initiating cells that are responsible for relapse. Since EGFR is altered in 50% of GBMs, it represents one of the most promising targets; however, EGFR kinase inhibitors have produced poor results in clinical assays, with no clear explanation for the observed resistance. We uncovered a fundamental role for the dual-specificity tyrosine phosphorylation-regulated kinase, DYRK1A, in regulating EGFR in GBMs. We found that DYRK1A was highly expressed in these tumors and that its expression was correlated with that of EGFR. Moreover, DYRK1A inhibition promoted EGFR degradation in primary GBM cell lines and neural progenitor cells, sharply reducing the self-renewal capacity of normal and tumorigenic cells. Most importantly, our data suggest that a subset of GBMs depends on high surface EGFR levels, as DYRK1A inhibition compromised their survival and produced a profound decrease in tumor burden. We propose that the recovery of EGFR stability is a key oncogenic event in a large proportion of gliomas and that pharmacological inhibition of DYRK1A could represent a promising therapeutic intervention for EGFR-dependent GBMs.

A Prognostic Model Based on Preoperative MRI Predicts Overall Survival in Patients with Diffuse Gliomas

BACKGROUND AND PURPOSE: Diffuse gliomas are classified as grades II–IV on the basis of histologic features, with prognosis determined mainly by clinical factors and histologic grade supported by molecular markers. Our aim was to evaluate, in patients with diffuse gliomas, the relationship of relative CBV and ADC values to overall survival. In addition, we also propose a prognostic model based on preoperative MR imaging findings that predicts survival independent of histopathology. MATERIALS AND METHODS: We conducted a retrospective analysis of the preoperative diffusion and perfusion MR imaging in 126 histologically confirmed diffuse gliomas. Median relative CBV and ADC values were selected for quantitative analysis. Survival univariate analysis was made by constructing survival curves by using the Kaplan-Meier method and comparing subgroups by log-rank probability tests. A Cox regression model was made for multivariate analysis. RESULTS: The study included 126 diffuse gliomas (median follow-up of 14.5 months). ADC and relative CBV values had a significant influence on overall survival. Median overall survival for patients with ADC < 0.799 × 10−3 mm2/s was <1 year. Multivariate analysis revealed that patient age, relative CBV, and ADC values were associated with survival independent of pathology. The preoperative model provides greater ability to predict survival than that obtained by histologic grade alone. CONCLUSIONS: ADC values had a better correlation with overall survival than relative CBV values. A preoperative prognostic model based on patient age, relative CBV, and ADC values predicted overall survival of patients with diffuse gliomas independent of pathology. This preoperative model provides a more accurate predictor of survival than histologic grade alone.

Preclinical Test of Dacomitinib, an Irreversible EGFR Inhibitor, Confirms Its Effectiveness for Glioblastoma

Glioblastomas (GBM) are devastating tumors in which there has been little clinical improvement in the last decades. New molecularly directed therapies are under development. EGFR is one of the most promising targets, as this receptor is mutated and/or overexpressed in nearly half of the GBMs. However, the results obtained with first-generation tyrosine-kinase inhibitors have been disappointing with no clear predictive markers of tumor response. Here, we have tested the antitumoral efficacy of a second-generation inhibitor, dacomitinib (PF299804, Pfizer), that binds in an irreversible way to the receptor. Our results confirm that dacomitinib has an effect on cell viability, self-renewal, and proliferation in EGFR-amplified ± EGFRvIII GBM cells. Moreover, systemic administration of dacomitinib strongly impaired the in vivo tumor growth rate of these EGFR-amplified cell lines, with a decrease in the expression of stem cell–related markers. However, continuous administration of the compound was required to maintain the antitumor effect. The data presented here confirm that dacomitinib clearly affects receptor signaling in vivo and that its strong antitumoral effect is independent of the presence of mutant receptor isoforms although it could be affected by the PTEN status (as it is less effective in a PTEN-deleted GBM line). Dacomitinib is being tested in second line for EGFR-amplified GBMs. We hope that our results could help to select retrospectively molecular determinants of this response and to implement future trials with dacomitinib (alone or in combination with other inhibitors) in newly diagnosed GBMs. Mol Cancer Ther; 14(7); 1548–58. ©2015 AACR.

Retinoblastoma (Rb) Tumor-Suppressor Pathway Alterations in Meningeal Hemangiopericytomas: High E2F Transcription Factor 1 Expression and Loss of Rb Expression Study by Double Immunofluorescence Staining and Laser-Scanning Confocal Microscopy

The authors analyzed the retinoblastoma (Rb) tumor‐suppressor pathway in meningeal hemangiopericytomas (MHPCs).

Consensus Recommendations from the Spanish Germ Cell Cancer Group on the Use of High-dose Chemotherapy in Germ Cell Cancer

BACKGROUND High-dose chemotherapy (HDCT) has been studied in several clinical scenarios in advanced germ cell cancer (GCC). OBJECTIVE To establish a clinical practice guideline for HDCT use in the treatment of GCC patients. DESIGN, SETTING, AND PARTICIPANTS An expert panel reviewed information available from the literature. The panel addressed relevant issues concerning and related to HDCT. The guideline was externally reviewed by two international experts. RESULTS AND LIMITATIONS The efficacy of HDCT has been demonstrated in selected GCC patients. The most conclusive evidence comes from retrospective analyses that need to be interpreted with caution. HDCT can cure a significant proportion of heavily treated GCC patients. When indicated, sequential HDCT with regimens containing carboplatin and etoposide, as well as peripheral stem-cell support, is recommended. There is no conclusive evidence to recommend HDCT as first-line therapy. According to a multinational retrospective pooled analysis, HDCT might be superior to conventional CT as first salvage treatment in selected patients. There is an urgent need for prospective clinical trials addressing the value of HDCT in GCC patients who experience failure on first-line cisplatin-based CT. In patients who progress on conventional-dose salvage CT, HDCT should be considered. Treatment of these patients at experienced centers is strongly recommended. CONCLUSIONS It has been demonstrated that HDCT cures selected GCC patients who experience disease progression on conventional rescue regimens. The panel recommends the inclusion of GCC patients in randomized clinical trials including HDCT. PATIENT SUMMARY This consensus establishes clinical practice guidelines for the use and study of high-dose chemotherapy in patients with germ cell cancer.

Analysis of response rate with ANTI PD1/PD-L1 monoclonal antibodies in advanced solid tumors: a meta-analysis of randomized clinical trials

Background Anti-PD1/PD-L1 monoclonal antibodies (mAbs) increase overall survival compared to standard of care (SOC) in different tumors. However, a proportion of patients (pts) will have progressive disease (PD) as best response. We conducted a meta-analysis to study the rates of response comparing these antibodies with SOC. Methods A search of published trials in MEDLINE and EMBASE analyzing anti-PD1/PD-L1mAbs monotherapy compared to SOC. Relative risk (RR) with 95% confidence interval (CI) of response rates between groups was estimated. Subgroup analyses for location of primary tumor, number of previous treatment lines, selected population by PD-L1 expression and type of radiological assessment were made. Results Twelve studies accounting for 6,700 pts were included (anti-PD1/PD-L1 mAbs: 3,451 pts; SOC: 3,249 pts [2,823 pts: chemotherapy, 426 pts: targeted therapy]). Adjusted response rates were (N, %): Complete Response (CR) (69/3153, 2.19%), Partial Response (PR) (596/3153, 18.90%), Stable Disease (SD) (632/2463, 25.66%) and PD (1027/2463, 41.70%); and CR (16/2955, 0.54%), PR (263/2955, 8.90%), SD (835/2269, 36.80%) and PD (834/2269, 36.76%) with anti-PD1/PD-L1 mAbs and SOC, respectively. Anti-PD1/PD-L1 mAbs improved CR rate (RR 3.48) and PR rate (RR 2.27). There were no differences in the PD rate between groups (RR 1.10). Subgroup analyses showed an improvement in clinical benefit with anti-PD1/PD-L1 mAbs for melanoma (RR 1.59; 1.37–1.84 95% CI) and those treated in the first line setting (RR 1.57; 1.27–1.95 95% CI). Conclusions Anti-PD1/PD-L1 mAbs increase overall response rate compared to SOC without an increase in PD rate. Melanoma and pts treated in first line setting seem to have greater benefit with anti-PD1/PD-L1 mAbs. Findings In this systematic meta-analysis, anti-PD1/PD-L1 mAbs were associated with a greater overall response rate. Patients with melanoma and those managed in the first line setting seem to have an additional benefit with anti-PD1/PD-L1 mAbs.

Perfusion MRI grading diffuse gliomas: Impact of permeability parameters on molecular biomarkers and survival

BACKGROUND AND PURPOSE Our objectives were: (1) compare dynamic susceptibility-weighted (DSC) and dynamic contrast-enhanced (DCE) permeability parameters, (2) evaluate diagnostic accuracy of DSC and DCE discriminating high- and low-grade tumors, (3) analyze relationship of permeability parameters with overall (OS) and progression-free survival (PFS) and (4) assess differences in high-grade tumors classified according to molecular biomarkers. MATERIALS AND METHODS 49 patients with histologically proved diffuse gliomas underwent DSC and DCE imaging. Parametric maps of cerebral blood volume (CBV), CBV-leakage corrected, volume transfer coefficient (Ktrans), fractional volume of the extravascular extracellular space (EES) (Ve), fractional blood plasma volume (Vp) and rate constant between EES and blood plasma (Kep) were calculated. High-grade gliomas were also classified according to isocitrate dehydrogenase (IDH), alpha-thalassemia/mental retardation syndrome X-linked (ATRX) and O6-methylguanine-dna-methyltransferase promoter methylation (MGMT) status. RESULTS There is correlation between parameters leakage, Ktrans and Vp. ROC curve analysis showed significance in both Ktrans and Ve for glioma grading. Threshold value of 0.075 for Ve generated the best combination of sensitivity (80%) and specificity (75%) in tumor gradation. Leakage was the only permeability parameter related to OS (P=0.006) and PFS (0.012); with prolonged survival for leakage values lower than 1.2. IDH-mutated high-grade tumors showed lower leakage and Ktrans values. High-grade tumors with loss of ATRX presented lower leakage and Vp values. CONCLUSIONS Both DSC and DCE permeability parameters serve as non-invasive method for glioma grading. Leakage was the unique permeability parameter related to survival and the best discriminating high-grade gliomas classified according to IDH and ATRX status.

Molecular Study of Long-Term Survivors of Glioblastoma by Gene-Targeted Next-Generation Sequencing

Glioblastoma (GBM) is the most common malignant adult primary brain tumor. Despite its high lethality, a small proportion of patients have a relatively long overall survival (OS). Here we report a study of a series of 74 GBM samples from 29 long-term survivors ([LTS] OS ≥36 months) and 45 non-LTS. Using next-generation sequencing, we analyzed genetic alterations in the genes most frequently altered in gliomas. Approximately 20% of LTS had a mutation in the IDH1 or IDH2 (IDH) genes, denoting the relevance of this molecular prognostic factor. A new molecular group of GBMs harbored alterations in ATRX or DAXX genes in the absence of driver IDH or H3F3A mutations. These patients tended to have a slightly better prognosis, to be younger at diagnosis, and to present frontal or temporal tumors, and, morphologically, to present giant tumor cells. A significant fraction of LTS GBM patients had tumors with 1 or more alterations in the relevant GBM signaling pathways (RTK/PI3K, TP53 and RB1). In these patients, the PDGFRA alteration is suggested to be a favorable molecular factor. Our findings here are relevant for developing future targeted therapies and for identifying molecular prognostic factors in GBM patients.

Dacomitinib: an investigational drug for the treatment of glioblastoma

ABSTRACT Introduction: Standard treatment of newly diagnosed glioblastoma (GB) is surgery with radiotherapy and temozolomide, but tumors will recur with a median overall survival of only 15 months. It seems imperative to explore new possibilities of treatment based on targetable alterations known to be present in GB. Among others, Epidermal Growth Factor Receptor or EGFR (HER1) mutations or amplifications are the most prevalent alterations in GB. In fact, around 40% of GB cases show amplification of EGFR gene, and half of these patients carry the EGFRvIII mutation, a deletion that generates a continuous activation of the tyrosine kinase domain of the receptor. Areas covered: We review the current knowledge about Dacomitinib, an oral, irreversible, second-generation, pan-HER tyrosine kinase inhibitor, in the treatment of glioblastoma. Dacomitinib has noteworthy antiglioma activity in preclinical models and has been tested in one phase II trial in patients with recurrent GB with EGFR amplification. Expert opinion: Despite the poor global results of Dacomitinib in recurrent GB shown in a phase II trial, some patients had a significant benefit. Therefore, it is necessary to improve the knowledge about the mechanisms of failure or resistance to EGFR inhibitors in GB.